Hidden guard Gu Zhaoning accidentally contracted a strange poison during a mission. Just as the poison flared up, she happened to run into her master Pei Jin, whose own cold poison was acting up. After sobering up, she realized that she had crossed boundaries with her master. With a grave mistake already made and in order to survive, she had no choice but to leave the hidden guard organization and begin a fugitive life. Who would have thought that the twists of fate would lead to a consort selection, once again bringing Gu Zhaoning and Pei Jin together under the identity of a duke estate's daughter, and even making her his Prince Regent consort. Entering the estate, Gu Zhaoning walked on the edge of exposure every day, while this unusual "ugly" consort she portrayed gradually made the cold-faced King of Hell, who had always kept women at a distance, fall hopelessly in love.